Expanding upon my addition to @baggvinshield’s post about Erebor’s technology, this post reiterates some of the ideas in my commentary there, and will be part of a future series on my headcanons over the practical feats of dwarvish engineering - specifically regarding their penchant for living in mountains.
These are some the main points I’ve determined necessary for bare-bones water management of a society living in such a resource-isolated place like Erebor. Currently, this post serves as a rough draft and will be the basis for further elaboration in later posts in the #Erebor Engineering series.
[Edit 20 May 2017: Now on AO3!]
As mentioned in my commentary, the hypothesis that the River Running not only runs underneath Erebor, but is also the driving force behind Erebor’s ability to comfortably host potentially tens of thousands of people in architectural splendor as the capital of the Dwarven state is a completely viable one.
Behind every great city, however, is a great waste management system toiling away in the background. The best-made systems, in my experience, are the ones nobody notices - or better yet, double their function as a veritable work of art. In this case, I seek to not only give Erebor’s water system those two functions, but many more.
With the constantly-circulating water this is a closed system that, if designed and maintained correctly, can support multiple uses. Having not only a method of disposal for all waste, but temperature control, electricity production, food supply opportunities, and social spaces in an aesthetically-pleasing manner means that dwarves can expend more effort on doing other things.
Of course, something this extensive would require a lot of manpower (dwarf-power?) in order to keep things running smoothly. This isn’t necessarily a bad thing, because it provides a plethora of job opportunities, and if this is both well-designed and well-maintained, then people can be spared to multi-task either different jobs or different parts of the system.
